Pulmonary injury following smoke inhalation represents a common clinical and pathological entity. How inhalation of smoke leads to bronchoconstriction, atelectasis and pulmonary infections remains unanswered. We have constructed a smoke exposure chamber with guidelines from the Committee on Fire Toxicology of the National Research Council for evaluating the toxicities of pyrolysis and combustion products in laboratory animals. Different degrees of smoke inhalation of the pyrolysis products of Douglas fir wood was achieved and was reflected by measuring the blood carboxyhemoglobin (COHb) levels of rabbits placed in the chamber. The mean COHb levels ranged from 7 to 40 percent. In addition we have demonstrated that there was an impairment in the phagocytic and bactericidal function of rabbit alveolar macrophages exposed to Douglas fir wood smoke thnt may partially explain the enhanced susceptibility of patients with smoke inhalation to pulmonary infections.